Pennsylvania Governor Tom Corbett signed a new law Friday designed to improve the detection of breast cancer.

The newly inked Breast Density Notification Act makes Pennsylvania the 11th state to require mammography centers to tell women if they have dense breast tissue.

Similar bills are in the works in 18 other states, including New Jersey. Breast cancer survivors whose tumors were initially missed on mammograms are pushing the bills.

The women of Pennsylvania are fighters, and this legislation gives them one more weapon to take on the fight, to defeat breast cancer, once and for all.

Dr. Mitchell Schnall is Penn Medicine's chief radiologist. He says the law is a good step forward. However, there's no clear guidance on what women should do with that information.

Advanced screening methods, such as ultrasound or MRIs, can help but have limitations.

"The downside of ultrasound is it's got a relatively high false positive," said Dr. Schnall.

False positives can lead to unnecessary biopsies.

Dr. Schnall believes new technology, like 3D mammograms, will boost detection, because those can see through dense tissue better. Still, he says density is only one factor in sizing up breast cancer risk. Family history, obesity, and unhealthy habits, such as smoking, play a role as well.

So women need to talk with their doctors to understand their risk, and this new bill will help.

The new Pennsylvania law does not require insurance companies to pay for additional screenings, such as MRI or ultrasound. So women may have to pay out-of-pocket for those, unless they can get it cleared by their insurance.